1. Field of the Invention
The invention relates generally to a headlamp assembly for a motor vehicle. More specifically, the invention relates to the cooling of a headlamp assembly by conducting heat from the light source to the exterior of the headlamp assembly via conductive heat sinks.
2. Related Technology
Headlamp assemblies have a light source, such as an incandescent lamp, a light emitting diode (LED) or high intensity discharge (HID) lamp, positioned within a headlamp chamber and electrically connected to a power source. The headlamp chamber is typically defined by a transparent or translucent lens, located forward of the light source, and a reflector located rearward and/or surrounding the light source. As used herein, the terms forward and rearward are referenced with respect to the position of the light source and the direction of the area that the light from the source is intended to illuminate. Thus, light from the assembly is intended to illuminate an area forward of the assembly.
During an operation cycle of the headlamp assembly, the light sources and other components of the lamp generate heat while “on” and cool while “off”, causing the chamber to undergoes temperature fluctuation and causing the air located within to expand and contract. To maintain a relative-constant chamber pressure, the chamber typically includes at least one opening that permits an air exchange between the chamber and the ambient air. However, to prevent contaminants, such as dust and debris, from entering the chamber, the opening is relatively small and is typically covered with an air-permeable membrane.
In order to attain the optimal performance of newer light sources, such as LED'S and their electrical components in the lamp assembly, it is desirable to maintain the internal temperature of the lamp assembly below the maximum operating temperature of these sources and components. Therefore, it is advantageous to provide the headlamp assembly with a mechanism that cools the chamber and the LED'S located therein.
Headlamp assemblies are also typically located on the vehicle in a position that is adjacent to the engine compartment. The temperature within the engine compartment is often significantly higher than the temperature outside of the engine compartment (the ambient temperature). For example, during operation of the vehicle, various components, such as the engine and the engine cooling system, output heat into the engine compartment. As another example, during periods of vehicle use and non-use, the air trapped within the engine compartment may become heated by solar energy. Therefore, it is advantageous to provide the headlamp assembly with a mechanism that isolates the chamber, and the light sources located therein, from the relatively high temperatures of the engine compartment.
In view of the above, it is beneficial to have a headlamp assembly that has a mechanism that effectively cools the assembly's internal components while minimizing air exchange between the inner chamber and the atmosphere and while isolating the inner chamber from the engine compartment and the relatively high temperatures associated therewith.